for good

From for (“over (a period of time)”, preposition) + good (“of an action: complete, thorough, utter”, adjective).

• "A bad haircut is no fun, but at least you’re not stuck with it for good, only until it grows out."
• "This day I left Chelsea for good (that's a genteel phrase) and am got into Suffolk street."
• "[S]he was dozing in the elbovv-chair, having refuſed to lie dovvn, ſaying, She ſhould ſoon, ſhe hoped, lie dovvn for good."
• "Well, now, I'm no scholar, and you're a lad as can read and figure; and, to put it straight, do you take it as a dead man is dead for good, or do he come alive again?"
• "What I want is to get out of this fix, for good—so I can go to sleep at night without worrying over what's going to happen to me tomorrow, and next month, and next year."
• "Yes, and thanks for the trouble you took from her eyes. I thought it was there for good so I never tried."
• "Whatever I said, whatever I did, I didn't mean it / I just want you back for good"
• "He […] unbuttons the bottom of his jacket so the rumors can be dispelled for good: he no longer wears his double belts."

• definitively
• forever
• for good and all
• once and for all
• permanently

• for better or worse
• till death do us part